This invention relates to power shifter controllers for controlling the operation of power shifters, which are used for transmission of cars or like vehicles for amplifying shifting action from change levers and transmitting the amplified shifting action to the transmission.
A car or like vehicle uses a power shifter having shift operation system, which provides shifting action coupled from a change lever (or a shift lever) via a shift cable to the power shifter, whereat amplifies said shift operation force with drive force of an electric motor and transmits the amplified shifting action force to a transmission.
FIG. 9 shows the relation between synchro load L on the transmission and synchro time t thereof in the operation of such a power shifter. As shown in the curve, in this power shifter the synchro load L varies with synchro time t in inverse proportion to the synchro time t. With reduction of the synchro time t, the power shifter performs faster shifting, and the synchro load L is increased. In the converse case, the synchro load is reduced.
The above power shifter, however, is required to always ensure shifting action with a constant shifting force under the above transmission characteristic. Hitherto, however, no technique which can perfectly meet such demand has been proposed.
In addition, the above prior art power shifter is subject to a commonly termed over-run phenomenon, i.e., a phenomenon that the rotational rate of the engine is increased beyond a permissible rotational rate range when a shifting action from a high to a low speed change stage is caused.
The above prior art power shifter has a further problem that a sensor may remain operative even after shifting action caused by change lever has been over. In such a case, unnecessary power is supplied to the electric motor, resulting in wasteful power consumption and possible damages to motor and drive components.